Abstract Background. Obesity is epidemic in the US and other industrialized countries and contributes significantly to population morbidity and mortality. Primary care physicians see a substantial portion of the obese population, yet rarely counsel patients to lose weight. Methods. Descriptive field notes of outpatient visits collected as part of a multimethod comparative case study were used to study patterns of physician–patient communication around weight control in 633 encounters in family practices in a Midwestern state. Results. Sixty-eight percent of adults and 35% of children were overweight. Excess weight was mentioned in 17% of encounters with overweight patients, while weight loss counseling occurred with 11% of overweight adults and 8% of overweight children. In weight loss counseling encounters, patients formulated weight as a problem by making it a reason for visit or explicitly or implicitly asking for help with weight loss. Clinicians did so by framing weight as a medical problem in itself or as an exacerbating factor for another medical problem. Conclusions. Strategies that increase the likelihood of patients identifying weight as a problem, or that provide clinicians with a way to “medicalize” the patient's obesity, are likely to increase the frequency of weight loss counseling in primary care visits.